Major Depression is a markedly impairing disorder that affects up to 20% of adolescents before adulthood, and is associated with significant impairment in adolescents'emotional and social development. While antidepressant medication and psychotherapy are effective in treating some depressed adolescents, approximately 30% fail to respond to a combination of these treatments. Furthermore, many families are reluctant to pursue antidepressant medication for depressed adolescents because of concerns about potentially increasing risk of suicidal ideation. Thus, there is a critical need for effective, non- pharmacological treatments for this population. One promising new intervention consists of modifying negative information-processing biases associated with depression. Recent research has suggested that these biases may be modified using a computerized program that provides repeated exposure to positive interpretations of salient, ambiguous situations, with the goal of interpreting ambiguity less negatively. These modification programs have been efficacious in altering interpretation biases and reducing anxiety in adults with social and specific phobias. Therefore, the proposed study aims to examine the efficacy of an adapted interpretation bias modification program for depressed adolescents. Specifically, the study will examine the efficacy of four sessions of the modification program in altering interpretation biases and reducing symptoms of depression, anxiety, and negative affect. A total of 60 adolescents (ages 14-21) with symptoms of major depression will be randomly assigned to either the immediate treatment condition (TX;four sessions of the modification program over two weeks) or the waitlist control condition (WL). Measures will include a diagnostic interview, self-report measures of depression, anxiety, and negative affect, and a test of interpretation bias in response to ambiguous situations. It is hypothesized that: 1) TX adolescents will interpret ambiguous scenarios less negatively (and show greater reduction in interpretation bias from pre- treatment) than WL adolescents at post-treatment, and 2) TX adolescents will experience less depression, anxiety, and negative affect at post-treatment (and greater reduction in these symptoms from pre-treatment), compared to WL adolescents. Relevance: Major depression is a seriously impairing disorder that affects as many as 20% of adolescents before adulthood. Many depressed adolescents do not benefit from existing treatments, underscoring the importance of developing new interventions. This study will examine how well a new cost-effective computerized intervention works to reduce symptoms of depression, anxiety, and negative affect in depressed adolescents.